msm: clock: Add a CXO voter for the LPM driver

The Low Power Mode resources driver needs to vote for
CXO in certain conditions. Add a voter clock for that
driver to the 9625/8226/8610 clock drivers.

Also, while we're here, create voter clocks for CXO
wherever necessary.

Change-Id: I07c9aed2ab67a58d296041a62049de63277995cd
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>